The present invention relates to the technical field of a stage apparatus for transporting substrates such as reticles, wafers and the like and further a scanning exposure apparatus and a device manufacturing method using the stage apparatus.
An exposure apparatus for transferring the fine pattern of a reticle onto a wafer on which a light sensitive agent is coated is used in a photolithographic process when semiconductors are manufactured.
Recently, there is a request for increasing an exposing region as the size of semiconductors increases. To satisfy this request. a scanning exposure apparatus employing a so-called step and scan system is proceeding toward practical utilization. This type of the scanning exposure apparatus irradiates slit- or arc-shaped illumination light onto a reticle, exposes a wafer at the reducing magnification of a projecting optical system in the long distance direction of a slit and exposes the wafer at the reducing magnification ratio of the projecting optical system in the short distance direction thereof while synchronizing the reticle with the wafer.
In a step and scan sequence, the reticle and the wafer are repeatedly accelerated and decelerated because they stop and move for each exposing shot. Since a force corresponding to the acceleration caused at the time and to the mass of the substrate (reticle or wafer) is applied to the substrate, the substrate must be held on a stage by a holding force which endures the above force. Ordinarily, the substrate is adsorbed to and held on the stage with a vacuum adsorbing force.
In order to more improve the capability of a device (improvement of processing throughput and an increase of a substrate size) and to enhance productivity hereinafter, it is unavoidable that the mass of a substrate is increased by an increase of a stage acceleration and an increase of a substrate size. However, since a larger force is required to hold a substrate as they are more increased, it has become difficult to hold the substrate against the acceleration only with the vacuum adsorbing force.
An object of the present invention made to solve the above problem is to provide a stage apparatus having a holding mechanism capable of coping with a larger acceleration and holding a larger substrate and an exposure apparatus of high productivity and a device manufacturing method using the stage apparatus.
To solve the above problem, a stage apparatus of the present invention includes a stage moving in a prescribed direction while holding a substrate; and a mechanism for activating a force which changes in accordance with an acceleration when the substrate moves on the stage from the direction of the acceleration, wherein a force for canceling the force acting on the substrate as the stage is accelerated is applied on the substrate.
Further, a stage apparatus of the present invention includes a stage moving in a prescribed direction while holding a substrate; a counter mass movable in a direction in which the moving direction component of the stage is included; and a mechanism for applying the torque of the moment generated by the counter mass to the substrate.
It is preferable that the mechanism has a lever supported by a hinge mechanism, an end of the lever is connected to the counter mass, and the lever imposes a force on a side of the substrate through the other end thereof to thereby apply a force for canceling the force acting on the substrate as the stage is accelerated.
It is preferable that a dispersed force is applied to a side of the substrate from the other end of the lever through a uniform pressure member.
It is preferable that the stage is reciprocatingly movable along a prescribed direction and a plurality of sets of the mechanisms is disposed on both sides of the substrate with respect to the moving direction of the stage so that the mechanisms can apply a force to the substrate when the substrate moves both forward and backward. As an example, four sets of the mechanisms are disposed to thereby apply forces to the four corners of the substrate.
It is preferable that the substrate is held to the stage with a vacuum adsorbing force.
It is preferable that the stage apparatus includes a unit for applying a pre-load to both sides of the substrate with respect to the moving direction thereof not only when the substrate is accelerated but also when the substrate is not accelerated. As an example, the unit for applying the pre-load has a spring connected to the counter mass.
It is preferable that when the mass of the substrate is represented by M and the maximum acceleration of a moving body until the moving body is accelerated from a stationary state to a constant speed state or until the moving body is decelerated from the constant speed state to the stationary state is represented by A, the pre-load f satisfies the condition |f|xe2x89xa7|Mxc3x97A|.
An exposure apparatus of the present invention includes an illuminating optical system for illuminating the prescribed illuminating region of a reticle, a projecting optical system for projecting the pattern in the illuminating region on the reticle onto a wafer by reducing the size of the pattern, a reticle stage movable in a prescribed direction with respect to the illuminating region and a wafer stage movable in a prescribed direction with respect to an exposing region which is conjugate with the illuminating region and performing scan exposure by moving the reticle stage and the wafer stage together with respect to the projecting optical system, wherein the stage apparatus discussed above is used as the reticle stage.
A device manufacturing method of the present invention includes manufacturing steps including a step for performing exposure using the above exposure apparatus.
Further objects and preferred aspects of the present invention will become apparent from the description of the following embodiments.